Yeah no chance.....

Zero..Zip...Nadda!
Of cource, he could have some type of super human sperm which could leap through his underpants, swim through his jeans, wriggle through your pants, dive beneth your undies and crawl up your vagina?
But...Probably not!
Sorry I couldn't resist. I remember those days.
I think that you can rest easy with the fact that you won't get pregnant from grinding fully clothed.
If you deffinatly dont want to get pregnant and plan on having penatration sex (penis in vagina) then please be safe and get yourself some condoms...Dont wait for him to get them. Take charge!
Hope this helps and at least put a smile on your face!

Nice sandra lol!!!